St. Louis, MISSOURI - Louisiana Purchase Exposition - Machinery Building - 1904: The Louisiana Purchase Exposition, informally known as the St. Louis World's Fair, was an international exposition held in St. Louis, Missouri, United States, from April 30 to December 1, 1904. Local, state, and federal funds totaling $15 million were used to finance the event. More than 60 countries and 43 of the 45 American states maintained exhibition spaces at the fair, which was attended by nearly 19.7 million people. Historians generally emphasize the prominence of themes of race and empire, and the fair's long-lasting impact on intellectuals in the fields of history, art history, architecture and anthropology. From the point of view of the memory of the average person who attended the fair, it primarily promoted entertainment, consumer goods and popular culture. This Undivded Back Era postcard, mailed in 1904, is in good condition, but there is some edge wear and soiling.